Firestore here explains, how I can use simple classes to directly use them with firestore: https://firebase.google.com/docs/firestore/manage-data/add-data
如何将字段标记为已排除？
data class Parent(var name: String? = null) {
// don't save this field directly
var questions: ArrayList<String> = ArrayList()
}
因为Kotlin为字段创建了隐式的getter和setter，所以您需要用@Exclude来注释setter，以告诉Firestore不要使用它们.Kotlin的语法如下所示:
data class Parent(var name: String? = null) {
// questions will not be serialized in either direction.
var questions: ArrayList<Child> = ArrayList()
@Exclude get
}